RFR: 8312262: Klass::array_klass() should return ArrayKlass pointer

[Calvin Cheung]

On Thu, 27 Jul 2023 20:16:17 GMT, Dean Long <dlong at openjdk.org> wrote:

>> This is a simple change to make array_klass() return ArrayKlass (the first dimension of TypeArrayKlass is a TypeArrayKlass so can't use ObjArrayKlass), higher_dimension is always an ObjArrayKlass and lower_dimension can be a TypeArrayKlass.  The change removes some casts.
>> Tested with tier1 linux/macosx/windows on x86 and aarch64.
>
> src/hotspot/share/oops/arrayKlass.hpp line 62:
> 
>> 60:   ObjArrayKlass* higher_dimension() const     { return _higher_dimension; }
>> 61:   inline ObjArrayKlass* higher_dimension_acquire() const; // load with acquire semantics
>> 62:   void set_higher_dimension(ObjArrayKlass* k) { _higher_dimension = k; }
> 
> The set_higher_dimension() function seems to be unused.  Should we remove it?

I'm using the function in the following PR https://github.com/openjdk/jdk/pull/14959.

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PR Review Comment: https://git.openjdk.org/jdk/pull/15059#discussion_r1276813629